1. Field of the Invention
The present invention relates to a magnetic head which is subjected to an air stream on a recording medium in a floating position or slides on a recording medium, and more particularly to a magnetic head in which a core assembly having a magnetic gap is mounted on a rail formed on a slider.
2. Description of the Related Art
In a magnetic head being subjected to an air stream on a recording medium in a floating position, a rail having a predetermined width is formed on opposing surfaces of a slider and a recording medium to form an ABS surface (air bearing surface) on the rail which is subjected to an air stream.
In a disk apparatus, for example, having a flexible disk for high density recording as a recording medium, on the rail surface of the slider, mentioned above, a core assembly formed by joining half-portions of the core across a magnetic gap is mounted thereon. For high density recording, because of a narrow track width, the width of the half-portion of the core forming the core assembly is sufficiently smaller than that of the rail forming the ABS surface.
Therefore, when the core assembly is mounted on the rail of the slider, a slot with a narrower width than that of the rail is to be formed in the rail of the slider to embed the core assembly therein.
The magnetic head of this configuration, however, presents problems as follows.
(1) As it is necessary to form a narrower slot in the rail of the slider than the width of the rail, it is very difficult to machine such a narrow slot, because the slider is as small as 3 mm on one side. PA0 (2) As the core assembly is embedded in the narrow slot formed in the rail of the slider, it is difficult to position and secure the half-portion of the core in the narrow slot. Accordingly, in mounting the core, some problems may be encountered, such as deviation of an azimuth angle of a magnetic gap by inclined mounting of the half-portion of the core in the slot, difficulty in precise positioning of the magnetic gap, and difficulty in precise setting of the depth of the magnetic gap from the surface of the rail (gap depth). PA0 (3) Since the slider and the half-portion of the core are made of materials that are different, their wearing states are different. When the slider is made of a ceramic of calcium titanate (Ti--O--Ca) and the half-portion of the core is made of ferrite, for example, the slider is prone to wear in comparison with the half-portion of the core. In the above-mentioned structure of the core assembly embedded in the surface of the rail with a narrower width than that of the rail, the wearing states differ in the surface of the rail and the half-portion of the core at the portion where the core assembly is mounted. This results in possibility of producing differences in level on the ABS surface (rail surface) in the width direction. The differences in level may affect the floating position of the slider on a recording medium and also may cause possible blemishes of the surface of the recording medium.